CN117320091A

CN117320091A - Session processing method and related equipment

Info

Publication number: CN117320091A
Application number: CN202311287368.6A
Authority: CN
Inventors: 朱强华; 李岩
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-08-15
Filing date: 2017-08-15
Publication date: 2023-12-29
Also published as: CN109548098B; BR112020003056A2; EP3668178A1; US20200187061A1; US20220217587A1; MX2020001834A; EP4247057A2; WO2019033796A1; CN109548098A; EP3668178A4; JP6908336B2; JP2020532180A; EP3668178B1; EP4247057A3; KR102347430B1; KR20200035152A; US11228951B2

Abstract

The embodiment of the application discloses a session processing method and related equipment, wherein the method comprises the following steps: the first AMF network element receives a first message from the second AMF network element, wherein the first message comprises information of a second network slice corresponding to a session currently performed by the terminal, and the session comprises one session or at least two sessions; the first AMF network element sends a first notification message to the second AMF network element under the condition that the second network slice corresponding to one session is not supported or the second network slice corresponding to all or part of at least two sessions is not supported, wherein the first notification message is used for notifying: the first AMF network element does not support a second network slice corresponding to one session or does not support a second network slice corresponding to all or part of at least two sessions; the second AMF network element releases the network resource corresponding to one session or releases the network resource corresponding to all or part of the sessions in at least two sessions. By adopting the method and the device, the waste of network resources can be reduced.

Description

Session processing method and related equipment

The present application is a divisional application, the original application number is 201710698407.X, the original application date is 2017, month 08, 15, the entire contents of which are incorporated herein by reference.

Technical Field

The present disclosure relates to the field of communications technologies, and in particular, to a session processing method and related devices.

Background

The network slicing technique enables the division of a physical network into multiple virtual networks. A virtual network is regarded as a 'network slice', each network slice is mutually independent, and each network slice is used for customizing and managing network functions according to the requirements of service scenes. There are multiple types of sessions currently in progress by one terminal, and different types of sessions may need to support network slices corresponding to the types to provide services.

In practical application, if the network slice corresponding to the session in the terminal is a network slice supported by an access and mobility management function (access and mobility management function, AMF) network element, the AMF network element can provide service for the session of the terminal, and if the network slice corresponding to the session in the terminal is a network slice not supported by the AMF network element, the AMF network element cannot provide service for the session of the terminal.

In the case that the terminal needs to re-register to the network, the access network device selects a new AMF network element for the terminal, and the AMF network element that previously provides service for the terminal is an old AMF network element, possibly due to the change of the location of the terminal, and the like. Or, as the terminal moves the position, the access network device needs to switch the AMF network element for the terminal, that is, the AMF network element to be switched to is a new AMF network element, and the AMF network element before switching is an old AMF network element. In the existing scheme, since the old AMF network element does not determine the session that the new AMF network element can provide the service and the session that the new AMF network element cannot provide the service, the old AMF network element still retains the information related to the session for the session that the new AMF network element cannot provide the service. If the old AMF network element does not receive the signaling about the session or receives the session inactivity notification of the terminal for a long time, the network resource corresponding to the session is released, which causes the waste of network resources.

Disclosure of Invention

The technical problem to be solved by the embodiments of the present application is to provide a session processing method and related devices, so as to reduce waste of network resources.

In a first aspect, an embodiment of the present application provides a session processing method, where the method includes: the second AMF network element sends a first message to the first AMF network element, wherein the first message comprises information of a second network slice corresponding to a session currently performed by the terminal, and the session comprises one session or at least two sessions; the first AMF network element sends a first notification message to the second AMF network element when the first AMF network element determines that the second network slice corresponding to one session is not supported or the second network slice corresponding to all or part of at least two sessions is not supported, wherein the first notification message is used for notifying the second AMF network element: the first AMF network element does not support a second network slice corresponding to one session or does not support a second network slice corresponding to all or part of at least two sessions; the second AMF network element releases the network resource corresponding to one session or releases the network resource corresponding to all or part of the sessions in at least two sessions.

In the first aspect, a first AMF network element sends a first notification message of a second network slice corresponding to a session where the first AMF network element does not support a terminal to a second AMF network element, and after the second AMF network element receives the first notification message, the second AMF network element can release network resources occupied by the session, so that waste of network resources is reduced.

In one possible implementation, before the first AMF network element sends the first notification message to the second AMF network element, the method further includes:

the first AMF network element determines that the second network slice corresponding to one session is not supported or the second network slice corresponding to all or part of the at least two sessions is not supported under the condition that the information of the first network slice supported by the first AMF network element does not contain the information of the second network slice corresponding to one session or the information of the first network slice does not contain the information of the second network slice corresponding to all or part of the at least two sessions;

or, the first AMF network element determines that the second network slice corresponding to one session is not supported or the second network slice corresponding to all or part of the at least two sessions is not supported when it is determined that the information of the allowed third network slice allocated to the terminal does not include the information of the second network slice corresponding to one session or the information of the third network slice allocated to the terminal does not include the information of the second network slice corresponding to all or part of the at least two sessions. Alternatively, the first AMF network element may obtain information about the allowed third network slice of the terminal from the NSSF network element.

In one possible embodiment, the method further comprises: the second AMF network element sends a second notification message to the SMF network element associated with the session identifier of one session or to the SMF network element associated with the session identifier of all or part of at least two sessions, where the second notification message is used to notify the SMF network element: the terminal has moved out of the slice service range of the second AMF network element. The SMF network element releases network resources occupied by the session of the terminal associated with the SMF network element, and the waste of the network resources is further reduced.

In one possible implementation, the SMF network element sends a third notification message to the UPF network element associated with the session identity of the session, the third notification message being used to notify the UPF network element: the terminal has moved out of the slice service range of the second AMF network element. The UPF network element releases network resources occupied by the session of the terminal associated with the UPF network element, thereby further reducing the waste of the network resources.

In one possible implementation, the first message is a context response message; in this case: before the second AMF network element sends the first message to the first AMF network element, the first AMF network element sends a context acquisition request of the terminal to the second AMF network element.

In one possible implementation manner, the first message further includes a mobility management context, a permanent identifier of the terminal, a session identifier, and an identifier of a session management function SMF network element associated with the session identifier, and the information of the second network slice corresponding to the session is information of a network slice supported by the SMF network element.

In one possible implementation, the first AMF network element sends a registration complete message to the terminal if it determines to support a second network slice corresponding to one session or to support a second network slice corresponding to all or part of at least two sessions.

In one possible implementation manner, the first message further includes a session identifier and an identifier of an SMF network element associated with the session identifier, and the information of the second network slice corresponding to the session is information of a network slice supported by the SMF network element.

In one possible implementation, the first AMF network element prepares network resources for one session or all or part of at least two sessions in case it is determined to support a second network slice corresponding to one session or to support a second network slice corresponding to all or part of at least two sessions.

In a possible implementation manner, the first message further includes a DNN of each session in the sessions currently performed by the terminal, so that the first AMF network element selects the SMF network element according to the DNN and the information of the second network slice corresponding to the supported session.

In one possible implementation manner, the second AMF network element releases the network resources corresponding to one session or releases the network resources corresponding to all or part of the sessions in at least two sessions, and one possible specific implementation manner is that the second AMF network element immediately releases the network resources corresponding to one session or releases the network resources corresponding to all or part of the sessions in at least two sessions when receiving the first notification message; one possible specific implementation manner is that the second AMF network element releases the network resource corresponding to one session or the network resource corresponding to all or part of the sessions in at least two sessions after a preset period of time under the condition that the second AMF network element receives the first notification message.

In a second aspect, an embodiment of the present application provides another session processing method, where the method includes: the method comprises the steps that a second AMF obtains information of a second network slice corresponding to a session currently performed by a terminal, wherein the session comprises one session or at least two sessions; the second AMF network element receives a first message from the network device, wherein the first message comprises an identifier of the first AMF network element to which the session is switched; and the second AMF network element releases the network resource corresponding to one session or releases the network resource corresponding to all or part of the at least two sessions under the condition that the second AMF network element does not support the second network slice corresponding to one session or the second network slice corresponding to all or part of the at least two sessions.

In the second aspect, the second AMF determines that the first AMF network element does not support the second network slice corresponding to all or part of the session in the terminal, so that the second AMF network element can release the network resources occupied by the unsupported session, thereby reducing the waste of network resources.

In a possible implementation manner, the network device may be a first AMF network element, or the network device is an NRF network element, which is not limited by the embodiment of the present invention.

In one possible implementation manner, before the second AMF network element releases the network resources corresponding to one session or releases the network resources corresponding to all or part of the sessions in at least two sessions, the method further performs: the second AMF network element determines that the first AMF network element does not support the second network slice corresponding to one session or does not support the second network slice corresponding to all or part of the sessions in the at least two sessions under the condition that the information of the first network slice supported by the first AMF network element does not comprise the information of the second network slice corresponding to one session or the information of the first network slice does not comprise the information of the second network slice corresponding to all or part of the sessions in the at least two sessions; or, if the second AMF network element determines that the information of the allowed third network slice allocated to the terminal does not include the information of the second network slice corresponding to one session or the information of the third network slice does not include the information of the second network slice corresponding to all or part of the at least two sessions, determining that the first AMF network element does not support the second network slice corresponding to one session or the second network slice corresponding to all or part of the at least two sessions. Optionally, the second AMF network element may obtain information about the allowed third network slice of the terminal from the NSSF network element. Thus, the second AMF network element can determine the session that the first AMF network element can provide the service and the session that the first AMF network element cannot provide the service.

In a possible implementation manner, the first message further includes information of a first network slice supported by the first AMF network element, so that the second AMF network element determines, according to the information of the first network slice, whether the information of the first network slice includes information of a second network slice corresponding to any session currently performed by the terminal, and further determines whether the first AMF network element can provide services for the session.

In one possible embodiment, the method further comprises: the second AMF network element sends a second notification message to a Session Management Function (SMF) network element associated with one session identifier or to an SMF network element associated with all or part of session identifiers in at least two sessions under the condition of releasing network resources corresponding to the one session or releasing network resources corresponding to all or part of sessions in the at least two sessions, wherein the second notification message is used for notifying the SMF network element: the terminal has moved out of the slice service range of the second AMF network element. The SMF network element releases network resources occupied by the session of the terminal associated with the SMF network element, and the waste of the network resources is further reduced.

In a possible implementation manner, the method further includes the second AMF network element sending, in a case where it is determined that the second network slice corresponding to one session is supported or the second network slice corresponding to all or part of at least two sessions is supported, a first notification message to the first AMF network element, where the first notification message is used to notify the first AMF network element: the first AMF network element supports a second network slice corresponding to one session or supports a second network slice corresponding to all or part of at least two sessions; the first AMF network element prepares network resources for all or part of one session or at least two sessions.

In a possible implementation manner, the method further includes that the first notification message further includes a DNN of a session corresponding to the second network slice supported by the first AMF network element, so that the first AMF network element selects the SMF network element according to the DNN and information of the second network slice corresponding to the supported session.

In a third aspect, an embodiment of the present application provides another session processing method, where the method includes: the method comprises the steps that a second AMF obtains information of a second network slice corresponding to a session currently performed by a terminal, wherein the session comprises one session or at least two sessions; the second AMF network element receives a first message from the network device, the first message including information of a first network slice supported by the first device; the second AMF network element releases network resources corresponding to the second session under the condition that the information of the first network slice does not contain the information of the second network slice corresponding to the second session; the second session is included in the sessions, and the sessions except the second session are the first session.

In the third aspect, by determining that the first AMF network element does not support the second network slice corresponding to all or part of the session in the terminal, the second AMF network element may release the network resource occupied by the unsupported session, so that the waste of the network resource is reduced.

In one possible embodiment, the method further comprises:

the second AMF network element sends a second notification message to the Session Management Function (SMF) network element associated with the second session identifier under the condition of releasing network resources corresponding to the second session, wherein the second notification message is used for notifying the SMF network element: the terminal has moved out of the slice service range of the second AMF network element. The SMF network element releases network resources occupied by the session of the terminal associated with the SMF network element, and the waste of the network resources is further reduced.

In one possible embodiment, the method further comprises: the second AMF network element sends a first notification message to the first AMF network element when the information of the first network slice is determined to contain the information of the second network slice corresponding to the first session, wherein the first notification message is used for notifying the first AMF network element: the information of the first network slice comprises information of a second network slice corresponding to the first session; the first AMF network element sends a fourth notification message to the second AMF network element under the condition that the first AMF network element does not support the second network slice corresponding to the third session, wherein the fourth notification message is used for notifying: the first AMF network element does not support the second network slice corresponding to a third session, which is all or part of the first session.

In one possible embodiment, the method further comprises: the first AMF network element sends a fourth notification message to the second AMF network element under the condition that the first AMF network element does not support the second network slice corresponding to the third session, wherein the fourth notification message is used for notifying: the first AMF network element does not support the second network slice corresponding to a third session, which is all or part of the first session. And the second AMF network element releases the network resource corresponding to the third session.

In one possible implementation, before the first AMF network element sends the fourth known message to the second AMF network element, the method further includes: the first AMF network element acquires information of an allowed third network slice distributed for the terminal; and the first AMF network element determines that the first AMF network element does not support the second network slice corresponding to the third session under the condition that the information of the third network slice does not contain the information of the second network slice corresponding to the third session. Alternatively, the first AMF network element may obtain information about the allowed third network slice of the terminal from the NSSF network element.

In one possible implementation, the first notification message further includes a DNN of the first session, so that the first AMF network element selects the SMF network element according to the DNN and information of the second network slice corresponding to the supported session.

In a fourth aspect, an embodiment of the present application provides a first AMF network element, where the first AMF network element has a function of implementing the behavior of the first AMF network element in the foregoing method design. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above.

In a possible implementation manner, the first AMF network element includes a processor configured to support the first AMF network element to perform the corresponding functions in the above method. Further, the first AMF network element may further comprise a communication interface for supporting communication between the first AMF network element and the second AMF network element or other network elements. Further, the first AMF network element may further comprise a memory for coupling with the processor, which holds the necessary program instructions and data of the first AMF network element.

In a fifth aspect, an embodiment of the present application provides a second AMF network element, where the second AMF network element has a function of implementing a second AMF network element behavior in the foregoing method design. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above.

In a possible implementation manner, the second AMF network element includes a processor configured to support the second AMF network element to perform the corresponding functions in the above method. Further, the second AMF network element may further comprise a communication interface for supporting communication between the second AMF network element and the first AMF network element, the SMF network element or other network elements. Further, the second AMF network element may further comprise a memory for coupling with the processor, which holds the necessary program instructions and data of the second AMF network element.

In a sixth aspect, an embodiment of the present application provides an SMF network element, where the SMF network element has a function of implementing SMF network element behavior in the foregoing method design. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above.

In a possible embodiment, the SMF network element comprises a processor configured to support the SMF network element to perform the corresponding functions of the above-described method. Further, the SMF network element may further comprise a communication interface, where the communication interface is configured to support communication between the SMF network element and the second AMF network element, the UPF network element, or other network elements. Further, the SMF network element may further comprise a memory for coupling with the processor, which holds the program instructions and data necessary for the SMF network element.

In a seventh aspect, an embodiment of the present application provides a UPF network element, where the UPF network element has a function of implementing a UPF network element behavior in the foregoing method design. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above.

In a possible embodiment, the UPF network element comprises a processor configured to support the UPF network element to perform the respective functions of the above method. Further, the UPF network element may further include a communication interface for supporting communication between the UPF network element and the SMF network element or other network elements. Further, the UPF network element may further comprise a memory for coupling to the processor, which holds the necessary program instructions and data for the UPF network element.

An eighth aspect provides a communication system comprising the first AMF network element according to the fourth aspect and the second AMF network element according to the fifth aspect; or comprises the first AMF network element according to the fourth aspect, the second AMF network element according to the fifth aspect and the SMF network element according to the sixth aspect; or the first AMF network element according to the fourth aspect, the second AMF network element according to the fifth aspect, the SMF network element according to the sixth aspect and the UPF network element according to the seventh aspect.

In a ninth aspect, a computer readable medium is provided for storing a computer program comprising instructions for performing the method of the first aspect or any possible implementation of the first aspect.

In a tenth aspect, a computer readable medium is provided for storing a computer program comprising instructions for performing the method of the second aspect or any possible implementation of the second aspect.

In an eleventh aspect, a computer readable medium is provided for storing a computer program comprising instructions for performing the method of the third aspect or any possible implementation of the third aspect.

In a twelfth aspect, there is provided a computer program product containing instructions which, when run on a computer, cause the computer to perform the method of the first aspect or any possible implementation of the first aspect.

In a thirteenth aspect, there is provided a computer program product containing instructions which, when run on a computer, cause the computer to perform the method of the second aspect or any possible implementation of the second aspect.

In a fourteenth aspect, there is provided a computer program product containing instructions which, when run on a computer, cause the computer to perform the method of the third aspect or any possible implementation of the third aspect.

Compared with the prior art, in the embodiment of the application, the first AMF network element can send the first notification message to the second AMF network element under the condition that the network slice corresponding to the session currently carried out by the self-supporting terminal is determined, so that the second AMF network element can timely perform the first network resource, and the waste of the network resource is reduced.

Drawings

Fig. 1 is a schematic architecture diagram of a communication system according to an embodiment of the present application;

FIG. 2A is a diagram of one possible scenario provided by embodiments of the present application;

FIG. 2B is another possible scene graph provided by an embodiment of the present application;

fig. 3 is a communication schematic diagram of a session processing method according to an embodiment of the present application;

fig. 4 is a communication schematic diagram of another session processing method according to an embodiment of the present application;

fig. 5 is a communication schematic diagram of another session processing method according to an embodiment of the present application;

fig. 6 is a communication schematic diagram of another session processing method according to an embodiment of the present application;

fig. 7 is a communication schematic diagram of still another session processing method according to an embodiment of the present application;

fig. 8 is a communication schematic diagram of still another session processing method according to an embodiment of the present application;

fig. 9 is a schematic block diagram of a first access network and a mobility management function network element provided in an embodiment of the present application;

Fig. 10 is a schematic block diagram of another first access network and a mobility management function network element provided in an embodiment of the present application;

fig. 11 is a schematic structural diagram of a first access network and a mobility management function network element provided in an embodiment of the present application;

fig. 12 is a schematic block diagram of a second access network and a mobility management function network element provided in an embodiment of the present application;

fig. 13 is a schematic block diagram of another second access network and a mobility management function network element provided in an embodiment of the present application;

fig. 14 is a schematic structural diagram of a second access network and a mobility management function network element provided in an embodiment of the present application;

fig. 15 is a schematic block diagram of a session management function network element provided in an embodiment of the present application;

fig. 16 is a schematic block diagram of another session management function network element provided in an embodiment of the present application;

fig. 17 is a schematic structural diagram of a session management function network element provided in an embodiment of the present application;

fig. 18 is a schematic block diagram of a user plane function network element provided in an embodiment of the present application;

fig. 19 is a schematic block diagram of another user plane function network element provided in an embodiment of the present application;

fig. 20 is a schematic structural diagram of a user plane function network element provided in an embodiment of the present application.

Detailed Description

Embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

Referring to fig. 1, fig. 1 is a schematic architecture diagram of a communication system according to an embodiment of the present application. The following describes the various network elements in fig. 1:

and (3) a terminal: may be a User Equipment (UE), a handheld terminal, a notebook computer, a subscriber unit (subscriber unit), a cellular phone (cellular phone), a smart phone (smart phone), a wireless data card, a personal digital assistant (personal digital assistant, PDA) computer, a tablet computer, a wireless modem (modem), a handheld device (handhold), a laptop computer (laptop computer), a cordless phone (cordless phone) or a wireless local loop (wireless local loop, WLL) station, a machine type communication (machine type communication, MTC) terminal or other network accessible device. The terminal and the access network equipment are communicated with each other by adopting a certain air interface technology.

Access network (radio access network, RAN) device: mainly responsible for radio resource management, quality of service (quality of service, qoS) management, data compression, encryption, etc. functions on the air interface side. The access network device may include various forms of base stations, such as: macro base stations, micro base stations (also referred to as small stations), relay stations, access points, and the like. In systems employing different radio access technologies, the names of base station-capable devices may vary, for example, in fifth generation (5th generation,5G) systems, referred to as gnbs; in the LTE system, it is called evolved NodeB (eNB or eNodeB); in the third generation (3rd generation,3G) system, it is called a Node B (Node B) or the like.

Access and mobility management function (access and mobility management function, AMF) network element: the method belongs to a core network element and is mainly responsible for signaling processing parts, namely control plane functions, including functions of access control, mobility management, attachment and detachment, gateway selection and the like. When the AMF network element provides a service for a session in the terminal, a storage resource of a control plane is provided for the session to store a session identifier, an SMF network element identifier associated with the session identifier, and the like.

Session management function (session management function, SMF) network element: responsible for user plane network element selection, user plane network element redirection, IP (internet protocol) address assignment, bearer establishment, modification and release, and QoS control.

Network warehouse function (NF Repository Function, NRF) network element: information of other network elements is stored, for example information of AMF network elements and SMF network elements.

User plane function (user plane function, UPF) network element: is responsible for forwarding and receiving user data in the terminal. User data can be received from the data network and transmitted to the terminal through the access network device; the UPF network element may also receive user data from the terminal via the access network device and forward the user data to the data network. The transmission resources and scheduling functions in the UPF network element that serve the terminal are managed and controlled by the SMF network element.

In the architecture shown in fig. 1, an access network device may communicate with at least one terminal; the access network device may be connected to at least one AMF network element. Wherein, one AMF network element may support one or more different types of network slices, and the types of network slices supported by different AMF network elements may be different. One AMF network element may establish communication connection with a plurality of SMF network elements, each SMF network element being located in one network slice instance, one SMF network element corresponding to a network slice supported by one AMF network element, and optionally, one SMF network element may be connected with a plurality of AMF network elements. In addition, one SMF network element may be connected to a plurality of UPF network elements, one UPF network element may be connected to one SMF network element, in which case, one SMF network element may manage and control a plurality of UPF network elements, one UPF network element being managed and controlled by one SPF. The UPF network element may establish a connection with the access network device to enable data transmission with respect to the terminal.

For example, one AMF network element establishes a connection with two SMF network elements, the two SMF network elements being a first SMF network element and a second SMF network element, respectively; the network slice types supported by the AMF network element comprise a network slice type 1 and a network slice type 2, the network slice type 1 corresponds to the network slice 1, the network slice type 2 corresponds to the network slice 2, and thus the first SMF network element is an SMF network element corresponding to the network slice 1, and the second SMF network element is an SMF network element corresponding to the network slice 2.

It should be noted that, in the embodiment of the present application, the information of the network slice corresponding to the session is used to indicate the information of the network slice capable of supporting the service type of the session, and the SMF network element associated with the session identifier represents the SMF network element that provides the service for the session.

Alternatively, in the embodiment of the present application, the network slice corresponding to the SMF network element may also be described as the network slice where the SMF network element is located. Further, the type of the same network slice may correspond to a plurality of network slice instances, so that a network slice corresponding to an SMF network element may also be described as a network slice instance corresponding to the SMF network element; the network slice in which the SMF network element is located may also be described as an example of the network slice in which the SMF network element is located, which is not limited in the embodiment of the present application.

In the process of registering the terminal to the network, the terminal sends the information of the configured network slice to the AMF network element through the access network equipment, for example, the information of the network slice can select auxiliary information (network service selection assistance information, NSSAI) for the network slice; the AMF network element decides which slice information is available for the UE according to the subscription of the terminal and the operator policy, and returns nsai information accepted by the network to the terminal. Then, in the process of establishing a session by the terminal, the terminal sends the received NSSAI information to the access network device, so that the access network device selects an AMF network element supporting the received NSSAI information for the terminal. Finally, the AMF network element selects an SMF network element for the terminal, and the SMF network element selects a UPF network element to provide session service for the terminal.

In practical application, if the network slice corresponding to the session of the terminal is a network slice supported by the AMF network element, the AMF network element may provide a service for the session of the terminal, and if the network slice corresponding to the session of the terminal is a network slice not supported by the AMF network element, the AMF network element may not provide a service for the session of the terminal.

Referring to fig. 2A, fig. 2A provides a schematic diagram of a possible scenario for the embodiment of the present application. As shown in fig. 2A, communication is performed between a terminal and an access network device, the access network device is respectively connected with a first AMF network element and a second AMF network element, the second AMF network element is respectively connected with an SMF network element 1, an SFM2 and an SMF network element 3, and the first AMF network element is respectively connected with an SMF network element 4 and an SFM 5. The second AMF network element supports a network slice 1, a network slice 2 and a network slice 3, the network slice where the smf network element 1 is located is the network slice 1, the network slice where the smf network element 2 is located is the network slice 2, and the network slice where the smf network element 3 is located is the network slice 3. The first AMF network element supports a network slice 1 and a network slice 4, the network slice where the smf network element 4 is located is the network slice 1, and the network slice where the smf network element 5 is located is the network slice 4.

Based on the scenario diagram of fig. 2A, for example, after the terminal is registered to the network through the access network device, the AMF network element that provides services for the session of the terminal is a second AMF network element, where the network slices corresponding to the session established by the terminal are network slice 1 and network slice 2. However, when the terminal is disconnected and in an idle state, and needs to re-register to the network, the access network device may select the first AMF network element for the terminal due to a change of the location of the terminal, and the network slices corresponding to the session to be restored of the terminal are network slice 1 and network slice 2, and the first AMF network element supports network slice 1 and does not support network slice 2, so that the first AMF network element can only restore the session corresponding to network slice 1 of the terminal. In the existing scheme, since the second AMF network element does not know the session that the first AMF network element can provide the service and the session that the first AMF network element cannot provide the service, the second AMF network element still retains the information related to the session corresponding to the network slice 1, and the SMF network element 2 associated with the session corresponding to the network slice 1 continues to wait for the signaling of the session. If the signaling related to the session is not received for a long time or the second AMF network element receives the UE session inactivity notification, the network resources corresponding to the session are released, for example, the control plane resources occupied by the session related information in the second AMF network element and the control plane resources occupied by the signaling in the SMF network element 2. This results in waste of network resources during unreleased time.

Further, referring to fig. 2B, fig. 2B provides another possible scene schematic diagram for the embodiment of the present application. As shown in fig. 2B, the terminal establishes a connection with the access network device 1, the access network device 1 connects with a second AMF network element, the second AMF network element establishes a connection with the SMF network element 6, the SFM7, and the SMF network element 8, the first AMF network element establishes a connection with the SMF network element 9, and the SFM10, respectively, and the first AMF network element establishes a connection with the access network device 2. The second AMF network element supports a network slice 1, a network slice 2 and a network slice 3, the network slice where the smf network element 6 is located is the network slice 1, the network slice where the smf network element 7 is located is the network slice 2, and the network slice where the smf network element 8 is located is the network slice 3. The network slice where the SMF network element 9 is located is network slice 1, and the network slice where the SMF network element 10 is located is network slice 4.

Based on the scenario diagram of fig. 2B, for example, after the terminal registers to the network through the access network device 1, the AMF network element that provides services for the session of the terminal is a second AMF network element, where the network slices corresponding to the session established by the terminal are network slice 1 and network slice 2. But as the terminal moves in position, the access network device 1 needs to switch AMF network elements for the terminal, the second AMF network element sends a network element discovery request to the NRF, and the NRF selects the first AMF network element for the terminal. Since the network slices corresponding to the session to be recovered in the terminal are the network slice 1 and the network slice 2, but the first AMF network element does not support the network slice 2, the first AMF network element can only recover the session corresponding to the network slice 1 in the terminal. In the existing scheme, since the second AMF network element does not know the session that the first AMF network element can provide the service and the session that the first AMF network element cannot provide the service, the second AMF network element still retains the information related to the session corresponding to the network slice 1, and the SMF network element 7 associated with the session corresponding to the network slice 1 continues to wait for the signaling of the session. Further alternatively, the UPF network element associated with the session corresponding to network slice 1 may continue to wait to receive packets for the session. If the signaling related to the session is not received for a long time or the second AMF network element receives the UE session inactivity notification, the network resources corresponding to the session are released, for example, the control plane resources occupied by the session related information in the second AMF network element, the control plane resources occupied by the signaling in the SMF network element 7, and the user plane transmission resources occupied by the session in the UPF network element. This results in waste of network resources.

It is noted that the information of each network slice referred to in any of the embodiments of the present application may include one or both of a network slice identification and single network slice selection assistance information (single network slice selection assistance information, S-NSSAI).

Wherein the network slice identity may be represented by at least one of the following (1) to (7).

(1) Network slice type information, for example, the Network slice type information may indicate Network slice types of enhanced mobile broadband services (enhanced mobile broadband, eMBB), ultra-reliable low latency communications (ultra-reliable low latency communications, URLLC), mass machine type communications (massive machine type communication, mctc), etc., and optionally, the Network slice type information may also indicate end-to-end Network slice types, including RAN-to-Core Network (CN) Network slice types, or may also refer to RAN-side Network slice types, or CN-side Network slice types.

(2) The service type information is related to a specific service, for example, the service type information may indicate service characteristics such as a video service, a car networking service, a voice service, etc., or information of the specific service.

(3) Tenant (tenant) information indicating customer information, such as Tencel, national grid, etc., that created or rented the network slice.

(4) User group information indicating grouping information for grouping users according to a certain characteristic, such as a user level, etc.

(5) Slice group information indicating that according to a certain feature, for example, all network slices that a terminal can access may be taken as one slice group, or groups of network slices may be divided according to other criteria.

(6) Network slice instance information for indicating an instance identifier created for the network slice and feature information, for example, an identifier may be allocated to the network slice instance for indicating the network slice instance, a new identifier may be mapped on the basis of the network slice instance identifier, the network slice instance may be associated, and the receiver may identify a specific network slice instance indicated by the identifier according to the identifier.

(7) A proprietary core network (dedicated core network, DCN) identity for uniquely indicating a proprietary core network in a long term evolution (Long Term Evolution, LTE) system or an enhanced LTE (eLTE) system, e.g. a core network specific to the internet of things, optionally, the DCN identity may be mapped with a network slice identity, the network slice identity may be mapped by the DCN identity, and the DCN identity may also be mapped by the network slice identity.

Wherein the S-NSSAI contains at least slice type/service type (SST) information, and optionally slice distinguishing information (slice differentiator, SD). The SST information is used to indicate the behavior of a network slice, such as the characteristics of the network slice and the type of service, and the SD information is complementary to the SST, and if the SST is implemented with multiple network slices, the SD may correspond to a unique network slice instance.

It should be understood that, in the embodiments of the present application, the network slice may use at least one of the above parameters to represent the information of the network slice, for example, the information of the network slice may be represented by a network slice type, or may be represented by a network slice type and a service type, or may be represented by service type tenant information, which is not limited in the embodiments of the present application, and how the information of the network slice is represented is not described in detail below. Optionally, the specific coding form of the information of the network slice is not limited, different fields of the interface message carried between different devices may represent the information of different network slices, or may be replaced by abstract index values, where the different index values correspond to different network slices, respectively. Of course, other identifiers besides the above-described ones are also possible, and are not limited herein. It should be understood that if the terminal, the access network device or the core network device supports multiple network slices, the information of the network slices supported by the terminal, the access network device or the core network device may be embodied in the form of a list of at least one identifier as described above.

The embodiment of the application can also be applied to other communication systems supporting network slicing. The term "system" may be used interchangeably with "network". The system architecture described in the embodiments of the present application is for convenience of describing the technical solution of the embodiments of the present application, and does not constitute a limitation on the technical solution provided in the embodiments of the present application, and as a person of ordinary skill in the art can know that, along with the evolution of the network architecture, the technical solution provided in the embodiments of the present application is applicable to similar technical problems.

Embodiments of the present application will be further described based on the above-described aspects of commonality referred to in the present application.

In the existing scheme, for example, in the two scenarios, for a session where a new AMF network element cannot provide services, an old AMF network element cannot timely send information related to the session, which causes waste of network resources.

In view of this, embodiments of the present application provide a session processing method, and a first AMF network element, a second AMF network element, an SMF network element, a UPF network element, and a system based on the method. The method comprises the following steps: the first AMF network element receives a first message from a second AMF network element, wherein the first message comprises information of a second network slice corresponding to a session currently performed by the terminal, and the session comprises one session or at least two sessions; the first AMF network element sends a first notification message to the second AMF network element under the condition that the second network slice corresponding to the session is not supported or the second network slice corresponding to all or part of the at least two sessions is not supported, wherein the first notification message is used for notifying the second AMF network element: the first AMF network element does not support the second network slice corresponding to the session or does not support the second network slice corresponding to all or part of the sessions in the at least two sessions; and the second AMF network element releases the network resources corresponding to the session or releases the network resources corresponding to all or part of the sessions in the at least two sessions. Wherein, the network resource corresponding to the session or the network resource corresponding to all or part of the at least two sessions may be referred to as a first network resource. For example, the method may be as shown in fig. 3.

In one example, before the first AMF network element sends the first notification message to the second AMF network element, the first AMF network element may further determine that the second network slice corresponding to the one session is not supported or the second network slice corresponding to all or part of the at least two sessions is not supported if it is determined that the information of the first network slice supported by the first AMF network element does not include the information of the second network slice corresponding to the one session or the information of the first network slice does not include the information of the second network slice corresponding to all or part of the at least two sessions; alternatively, the first AMF network element may further determine that the second network slice corresponding to the one session is not supported or the second network slice corresponding to all or part of the at least two sessions is not supported, if it is determined that the information of the allowed third network slice allocated to the terminal does not include the information of the second network slice corresponding to the one session or the information of the third network slice allocated to the terminal does not include the information of the second network slice corresponding to all or part of the at least two sessions.

In one possible implementation, the first message may be a context response message, and before the first AMF network element receives the first message from the second AMF network element, the context acquisition request of the terminal may also be sent to the AMF network element.

In such an embodiment, the first message may also include a mobility management context, a permanent identity of the terminal, a session identity, and an identity of the SMF network element associated with the session identity. In this case, the information of the second network slice corresponding to the session is information of a network slice supported by the SMF network element.

In this embodiment, the first AMF network element may further send a registration completion message to the terminal in case it determines to support the second network slice corresponding to the one session or to support the second network slice corresponding to all or part of the at least two sessions.

In another possible embodiment, the first message may further comprise a session identity and an identity of an SMF network element associated with the session identity. In this case, the information of the second network slice corresponding to the session is information of a network slice supported by the SMF network element.

In this embodiment, the first AMF network element may further prepare network resources for the one session or all or part of the at least two sessions in case it is determined to support the second network slice corresponding to the one session or to support the second network slice corresponding to all or part of the at least two sessions. Wherein the network resources referred to herein may be referred to as second network resources.

In one example, the first message may also include a data network name (data network name, DNN) for each of the sessions currently ongoing by the terminal.

In one example, the second AMF network element may release the first network resource immediately upon receiving the first notification message, or may also release the first network resource after a preset period of time.

Further, the second AMF network element may further send a second notification message to the SMF network element associated with the one session identifier or to the SMF network element associated with all or part of the session identifiers in the at least two sessions, where the second notification message is used to notify the SMF network element: the terminal moves out of the slicing service range of the second AMF network element; and the SMF network element releases network resources occupied by the session associated with the SMF network element of the terminal. Wherein the network resources occupied by the session of the terminal associated with the SMF network element may be referred to as third network resources.

Further, the SMF network element may further send a third notification message to the UPF network element associated with the session identifier, where the third notification message is used to notify the UPF network element: the terminal moves out of the slicing service range of the second AMF network element; and the UPF network element releases network resources occupied by the session associated with the UPF network element of the terminal. Wherein the network resource occupied by the session of the terminal associated with the UPF network element may be referred to as a fourth network resource.

In the embodiment of the application, the first AMF network element can send the first notification message to the second AMF network element under the condition that the network slice corresponding to the session currently carried out by the self-supporting terminal is determined, so that the second AMF network element can timely perform the first network resource, and the waste of the network resource is reduced.

The method shown in fig. 3 is described in further detail below in conjunction with fig. 4 and 5.

Based on the scene diagram of fig. 2A, please refer to fig. 4, a flow diagram of a session processing method is provided for an embodiment of the present application. As shown in fig. 4, the method is implemented interactively by the first AMF network element, the second AMF network element, the terminal, the RAN, and the SMF network element. Wherein, the terminal is in a connection state and serves as a second AMF network element; after the terminal is changed from the connection state to the idle state, the RAN determines a first AMF network element serving the terminal in the process of re-registering the network, and the first AMF network element and the second AMF network element are different AMF network elements. For a session corresponding to a network slice not supported by the first AMF network element, the second AMF network element and the SMF network element selected by the second AMF network element still reserve corresponding control plane resources for the session.

And 401, the terminal sends a registration request and the information of the network slice corresponding to the current session in the terminal to the RAN through the radio resource control signaling.

Among other things, radio resource control (radio resource control, RRC) signaling may include information of a registration request and a network slice corresponding to a session currently ongoing in the terminal. For example, the registration request is registration request; for example, the information of the network slice corresponding to the session currently performed by the terminal is S-nsai). The terminal sends a registration request to the RAN through RRC signaling to register to the network, and carries network slice information in the RRC signaling, so that the RAN determines a first AMF network element for providing service for the terminal.

Optionally, the session currently performed by the terminal may be the same as or different from the session previously established in the second AMF network element, which is not limited in this embodiment of the present application.

Accordingly, the RAN receives a registration request in the RRC signaling sent by the terminal and information of a network slice corresponding to a session currently performed by the terminal.

The ran determines 402 a first AMF network element serving the terminal.

The RAN selects one AMF network element from at least one AMF network element through the information of the network slice included in the RRC signaling, and determines the selected AMF network element as a first AMF network element.

In a first alternative manner, the RAN may arbitrarily select one of the at least one AMF network element to determine as the first AMF network element.

Or in a second alternative manner, the RAN may select, from at least one AMF network element, an AMF network element supporting all or part of network slices corresponding to the session currently in progress as the first AMF network element. Therefore, the first AMF network element is selected for the current session of the terminal on the premise of determining the network slice supported by the AMF network element, and the probability of successful establishment of the session in the terminal in the first AMF network element can be improved.

Optionally, the RAN may determine information of network slices supported by each AMF network element in the at least one AMF network element, so as to select, from the at least one AMF network element, an AMF network element supporting all or part of network slices corresponding to the session currently performed as the first AMF network element.

For example, if the session currently performed by the terminal includes a first session, a second session, and a third session; the first session corresponds to a first network slice, the second session corresponds to a second network slice, and the third session corresponds to a third network slice; then, if at least one AMF network element exists which supports the first network slice, the second network slice and the third network slice, the RAN selects the AMF network element which can support the three network slices as a first AMF network element; or if at least one AMF network element has at most any two AMF network elements capable of supporting the two network slices, the RAN selects the AMF network element capable of supporting the two network slices as a first AMF network element. This is not enumerated here for other cases. It can be seen that the RAN may implement determining the first AMF network element according to the network slice supported by the at least one AMF network element and the network slice corresponding to the session currently performed in the terminal.

403, the ran sends a registration request to the first AMF network element.

Specifically, the RAN sends a registration request to the first AMF network element, where the request carries an identifier of a second AMF network element that provides services for the terminal before the terminal sends the registration request and in a connected state, so that the first AMF network element can implement communication with the second AMF network element according to the identifier of the second AMF network element.

Correspondingly, the first AMF network element receives a registration request sent by the RAN.

404, the first AMF network element sends an information acquisition request to the second AMF network element.

Specifically, the first AMF network element sends an information acquisition request to the second AMF network element according to the identifier of the second AMF network element. For example, the information acquisition request may be a context acquisition request. Or the information acquisition request is an acquisition request of information of a network slice, and the acquisition request is used for acquiring information of a second network slice corresponding to a session currently performed by the terminal.

Further, the information obtaining request carries the identifier of the terminal, so that the second AMF network element obtains the information of the second network slice corresponding to the session in the terminal according to the identifier of the terminal.

Correspondingly, the second AMF network element receives the information acquisition request sent by the first AMF network element.

And 405, the second AMF network element sends a first message to the first AMF network element, wherein the first message comprises information of a second network slice corresponding to the session currently performed by the terminal.

Optionally, if the information acquisition request is a context acquisition request, the first message further includes a mobility management context, a permanent identifier of the terminal, a session identifier, and an identifier of an SMF network element associated with the session identifier. And the second AMF network element determines the current session of the terminal and the mobile management context corresponding to the session according to the permanent identification and the session identification of the terminal, and further determines the information of the second network slice corresponding to the session according to the identification of the SMF network element associated with the session identification. And the information of the second network slice corresponding to the session is the information of the network slice supported by the SMF network element.

After the second AMF network element selects the SMF network element for the session of the terminal, the session identifier and the SMF network element identifier associated with the session identifier are stored in an associated manner, so that the second AMF network element can transmit through the SMF network element indicated by the corresponding SMF network element identifier when receiving the data packet related to the session. And storing information of a second network slice supported by the SMF network element, so that the second AMF network element determines information of the network slice required by the session.

Optionally, the first message further includes a data network name (data network name, DNN) of each session in the session currently performed by the terminal, so that in the case that a supported session exists, the first AMF network element selects the SMF network element according to the DNN and information of a second network slice corresponding to the supported session.

Correspondingly, the first AMF network element receives a first message sent by the second AMF network element.

The first AMF network element determines whether the first AMF network element supports a second network slice corresponding to one session or whether the first AMF network element supports a second network slice corresponding to all or part of at least two sessions 406.

Wherein the session currently ongoing by the terminal comprises one session or at least two sessions. For the case that the current session of the terminal comprises one session, the first AMF network element judges whether the first AMF network element supports a second network slice corresponding to the session; for the case that the session currently performed by the terminal includes at least two sessions, the first AMF network element determines whether the first AMF network element supports second network slices corresponding to all or part of the at least two sessions.

If the first AMF network element determines that the first AMF network element supports the second network slice corresponding to one session or supports the second network slice corresponding to all sessions in at least two sessions, step 407 is not executed, step 408 is executed, and the first AMF network element sends a registration accept message to the terminal.

The first AMF network element determines that the first AMF network element supports a second network slice corresponding to a partial session of the at least two sessions, where the supported partial session is determined to be the first partial session and the other partial session not supported is determined to be the second partial session. In this case, the first AMF network element performs step 407 to send a first notification message to the second AMF network element that the second network slice corresponding to the second partial session is not supported. In addition, the first AMF network element performs step 408 of sending a registration accept message to the terminal.

The first AMF network element performs step 407 when determining that the first AMF network element does not support a second network slice corresponding to one session or does not support a second network slice corresponding to all sessions in at least two sessions, and sends a first notification message to the second AMF network element, where the first notification message does not support the second network slice corresponding to all sessions. And step 407 is not performed.

Further, the first AMF network element determines whether the first AMF network element supports a second network slice corresponding to any one session, which specifically includes: the first AMF network element judges whether the information of the first network slice contains the information of the second network slice corresponding to the session according to the information of the first network slice supported by the first AMF network element, and if the information of the first network slice does not contain the information of the second network slice, the first AMF network element does not support the second network slice corresponding to the session. And when the information of the first network slice comprises the information of the second network slice, then the first AMF network element acquires the information of the allowed third network slice allocated to the terminal, and the first AMF network element judges whether the information of the allowed third network slice comprises the information of the second network slice corresponding to the session. And if the information of the allowed third network slice does not contain the information of the second network slice corresponding to the session, the information indicates that the first AMF network element does not support the second network slice corresponding to the session. If the information of the allowed third network slice includes the information of the second network slice corresponding to the session, the information indicates that the first AMF network element supports the network slice corresponding to the session. For example, the first AMF network element obtains information about the allowed third network slice of the terminal from a network slice selection function (network slice selection function, NSSF) network element, and optionally, for different AMF network elements, the information about the allowed third network slice of the terminal may be the same or different, which is not limited in the embodiments of the present application. In this embodiment of the present application, the acquired information of the allowed third network slice allocated to the terminal is for the first AMF network element.

In other words, whether the first AMF network element does not support the second network slice due to the deployment reason of the network slice of the first AMF network element is realized by judging whether the information of the first network slice contains the information of the second network slice corresponding to the session according to the information of the first network slice supported by the first AMF network element; and then judging whether the first AMF network element does not support the second network slice due to policy reasons or not by judging whether the information of the allowed third network slice comprises the information of the second network slice corresponding to the session or not.

For example, the information of the first network slice supported by the first AMF network element is a network slice A1, a network slice A2, and a network slice A3, and the information of the second network slice corresponding to the session currently performed by the terminal is a first session corresponding network slice A1, a second session corresponding network slice A3, and a third session corresponding network slice A4. Therefore, since the information of the network slice supported by the first AMF network element includes the network slice A1 and the network slice A3, the first AMF network element supports the network slice A1 corresponding to the first session and the network slice A3 corresponding to the second session.

407, the first AMF network element sends a first notification message to the second AMF network element when determining that the second network slice corresponding to the one session is not supported or the second network slice corresponding to all or part of the at least two sessions is not supported.

Wherein, the first notification message is used for notifying the second AMF network element: the first AMF network element does not support the second network slice corresponding to the one session or does not support the second network slice corresponding to all or part of the at least two sessions, so that the second AMF network element can determine which second network slices corresponding to the sessions are not supported by the first AMF network element.

Optionally, in a case that the first AMF network element determines that the first AMF network element does not support the second network slice corresponding to one session or does not support the second network slice corresponding to all or part of the sessions in the at least two sessions, the first notification message may further carry indication information, for example, unsupported slice. For example, the first notification message carries indication information and an unsupported session identifier; or carrying indication information and an SMF network element identifier associated with a non-supported session identifier; or, carrying indication information, unsupported session identification and an SMF network element identification associated with the unsupported session identification.

Alternatively, the first notification message may be indicated by an information element (information element, IE), a flag, a cause value (cause), or the like, which is not limited by the embodiment of the present application. For example, the first notification message is a preset first cause value, and the first cause value is used to indicate that the first AMF network element does not support the network slice corresponding to the session.

For example, it is premised that the session currently performed by the terminal includes a first session, a second session, and a third session. And for the first AMF network element, the first session and the second session can be provided with services, and the network slice corresponding to the third session is not supported, so that the first notification message sent by the first AMF network element to the second AMF network element comprises the identification of the third session and the corresponding first cause value.

Optionally, the first AMF network element determines that the first AMF network element supports a second network slice corresponding to a partial session of the at least two sessions, where the supported partial session is determined as a first partial session and the other partial session not supported is determined as a second partial session. In one possible approach, the first notification message may include at least one of a session identity of the first partial session and an SMF network element identity associated with the session identity of the first partial session. Optionally, indication information, such as supported slice, may also be carried. Because the second AMF network element can determine the session identifier of the plurality of sessions currently performed in the terminal, the second AMF network element can also determine the second network slice not supported by the first AMF network element through the first notification message supporting the second network slice. In another possible solution, the first notification message may include at least one of a session identity of the second partial session and an SMF network element identity associated with the session identity of the second partial session. Optionally, an indication may also be carried, for example unsupported slice. In yet another possible solution, the first notification message may include at least one of a session identifier of the supported first partial session and an SMF network element identifier associated with the session identifier of the first partial session, and further includes at least one of a session identifier of the unsupported second partial session and an SMF network element identifier associated with the session identifier of the second partial session, so that the second AMF network element directly determines the supported second network slice and the unsupported second network slice.

Correspondingly, the second AMF network element receives the first notification message sent by the first AMF network element.

The first AMF network element sends 408 a registration accept message to the terminal.

Optionally, the first AMF network element may allocate a temporary identifier to the terminal, and send the new temporary identifier to the terminal with the new temporary identifier carried in the registration receiving message.

Optionally, the first AMF network element may also perform security authentication on the terminal before performing step 408. The security authentication comprises authentication of a terminal, authentication of multiple users, use authorization and policy verification of the multiple users, and confidentiality and integrity protection of signaling messages in the terminal.

409, the terminal sends a registration complete message to the first AMF network element.

Specifically, under the condition that the registration receiving message carries the first AMF network element to allocate a temporary identifier for the terminal, the terminal sends a registration completion message to the first AMF network element.

It should be noted that, in the embodiment of the present application, the data of the communication between the first AMF network element or the second AMF network element and the terminal is forwarded through the RAN.

410, the second AMF network element releases the first network resource corresponding to the one session or releases the first network resource corresponding to all or part of the at least two sessions.

Specifically, after step 407, the second AMF network element determines that the first AMF network element does not support the second network slice corresponding to the one session or does not support the second network slice corresponding to all or part of the at least two sessions, and then the second AMF network element releases the first network resources corresponding to the non-supported sessions.

For any one unsupported session, the first network resource released by the second AMF network element includes a control plane storage resource corresponding to the session. For example, the second AMF network element stores the session identifier of the session, the SMF network element identifier associated with the session identifier, the information of the network slice corresponding to the SMF network element, and the like, and the first network resources are released by receiving the first notification message, so that the waste of the first network resources is reduced.

In an alternative manner, in the case that the second AMF network element receives the first notification message, the second AMF network element immediately releases the first network resource corresponding to the unsupported session. Or in another alternative manner, in the case that the second AMF network element receives the first notification message, the second AMF network element releases the first network resource corresponding to the unsupported session after a preset period of time. For example, the second AMF network element starts a timer, and after the timer finishes, releases the first network resources corresponding to all or part of the sessions, so as to prevent the ping-pong effect of the terminal, that is, prevent frequent movement of the terminal position, and cause signaling load of the core network.

For example, if the terminal moves from the first AMF network element to the service range of the second AMF network element when the timer is not completed, the second AMF network element may reuse the first network resources corresponding to the unsupported sessions in the original terminal, so that the network resources required by the second AMF network element to reestablish the unsupported sessions can be avoided by the timer, so as to reduce the waste of signaling in the core network.

For another example, when the terminal moves to the service range of the first AMF network element in the timely process of the timer, the first network resource corresponding to the unsupported session is released after the timer finishes timing.

In case the second AMF network element releases the first network resources corresponding to the unsupported sessions, the second AMF network element performs step 411 to inform the SMF network element associated with each of the unsupported sessions.

411, in the case that the second AMF network element releases the first network resource corresponding to the one session or releases the first network resource corresponding to all or part of the at least two sessions, the second AMF network element sends a second notification message to the SMF network element associated with the one session identifier or to the SMF network element associated with all or part of the at least two sessions.

The second notification message is configured to notify the SMF network element that the terminal has moved out of the slice service range of the second AMF network element. Namely, under the condition that the second AMF network element determines to release the first network resource, the SMF network element is informed to release the third network resource so as to reduce the waste of network resources at the side of the SMF network element.

Optionally, the second AMF network element may determine, through a correspondence between the session identifier and the SMF network element identifier, an SMF network element that provides a session service for the session; furthermore, the second AMF network element may send a second notification message to the corresponding SMF network element and carry a session identifier of the session, so that the SMF network element releases the third network resource occupied by the session. For example, the session that the second AMF network element previously provides services for the terminal includes a first session and a second session, where the first session corresponds to the first SMF network element, and the second session corresponds to the second SMF network element, so, when the terminal has moved out of the slice service range of the second AMF network element, the second AMF network element sends second notification messages to the first SMF network element and the second SMF network element, where the notification messages sent to the first SMF network element carry the session identifier of the first session, and the second notification messages sent to the second SMF network element carry the session identifier of the second session, so that each SMF network element releases the third network resource, so as to reduce the waste of network resources on the side of each SMF network element.

Correspondingly, the SMF network element receives a second notification message from the second AMF network element.

412, the SMF network element releasing a third network resource occupied by a session of the terminal associated with the SMF network element.

Specifically, in the case that the SMF network element receives the second notification message, the SMF network element releases a third network resource occupied by a session associated with the SMF network element of the terminal, so as to reduce a waste of network resources in an SMF network element side.

It should be noted that, the SMF network element herein is any one of at least one SMF network element to be notified by the second AMF network element, and other SMF network elements notified by the second AMF network element may release corresponding network resources according to the scheme in step 411.

The third network resources released by the SMF network element include a session context indicated by a session identifier corresponding to the SMF network element identifier, the session context includes DNN, qoS data Flow (QoS Flow) information, and the like, and includes transmission resources (such as a transport layer address and a tunnel address), and the third network resources are released by receiving the second notification message, so that waste of the third network resources is reduced.

In an alternative manner, in the case that the SMF network element receives the second notification message, the SMF network element immediately releases the third network resource occupied by the session associated with the SMF network element.

In the embodiment of the application, the first AMF network element sends the first notification message of the second network slice corresponding to the session of which the first AMF network element does not support the terminal to the second AMF network element, and after the second AMF network element receives the first notification message, the second AMF network element can release the network resource occupied by the session, so that the waste of the network resource is reduced. In addition, the second AMF network element informs the SMF network element that the terminal moves out of the service range of the second AMF network element, so that the SMF network element can release the network resources occupied by the session, and the waste of the network resources is further reduced.

Referring to fig. 5, a schematic flow chart of a session processing method is provided for an embodiment of the present application based on the scene graph of fig. 2B. As shown in fig. 5, the method is implemented interactively by a first AMF network element, a second AMF network element, a terminal, a RAN, an NRF network element, an SMF network element, and a UPF network element. Wherein, in the scene that the terminal needs to switch AMF network element; the second AMF network element is an AMF network element for providing service for the terminal before switching, the first AMF network element is an AMF network element to which the terminal is to be switched, which is determined by the NRF network element, and the first AMF network element and the second AMF network element are different AMF network elements. For the session corresponding to the network slice not supported by the first AMF network element, the second AMF network element and the second AMF network element still reserve corresponding control plane resources for the SMF network element selected by the session, and the UPF network element selected by the session still reserves corresponding user plane resources.

501, the ran sends a handover request of the terminal to the second AMF network element.

Specifically, in the case where it is necessary to switch AMF network elements for the terminal due to the position movement of the terminal or load balancing, the RAN sends a handover request of the terminal to the second AMF network element.

502, the second AMF network element sends a network element discovery request to the NRF network element.

For example, the network element discovery request is NF Discovery request. The network element discovery request includes an identifier of the terminal, so that the NRF network element determines an AMF network element that provides services for the terminal.

Correspondingly, the NRF network element receives a network element discovery request sent by the second AMF network element. And determining a first AMF network element that serves the terminal.

In a first alternative manner, the NRF network element may arbitrarily select one to be determined as the first AMF network element from at least one AMF network element.

Or in the second alternative, the NRF network element may select, from at least one AMF network element, an AMF network element supporting all or part of network slices corresponding to the session currently performed as the first AMF network element. Therefore, the first AMF network element is selected for the current session of the terminal on the premise of determining the network slice supported by the AMF network element, and the probability of successful establishment of the session in the terminal in the first AMF network element can be improved.

Optionally, the NRF network element may determine information of a network slice supported by each AMF network element in the at least one AMF network element, so as to select, from the at least one AMF network element, an AMF network element supporting all or part of network slices corresponding to the session currently performed as the first AMF network element.

503, the nrf network element sends the determined identification of the first AMF network element providing the service for the terminal to the second AMF network element.

Correspondingly, the second AMF network element receives the identification of the first AMF network element sent by the NRF network element.

Optionally, the identification of the first AMF network element is carried in a network element discovery response, for example, the network element discovery response is NF Discovery response.

504, the second AMF network element sends a first message to the first AMF network element, where the first message includes information of a corresponding second network slice currently performed by the terminal.

Specifically, the second AMF network element sends the first message to the first AMF network element according to the identifier of the first AMF network element sent by the NRF network element.

Alternatively, the first message may be a redirect request, such as relocation request.

Optionally, the first message further includes a session identifier and an identifier of an SMF network element associated with the session identifier, the second AMF network element determines, according to the session identifier, a session currently performed by the terminal, and further determines, according to the identifier of the SMF network element associated with the session identifier, information of a second network slice corresponding to the session. And the information of the second network slice corresponding to the session is the information of the network slice supported by the SMF network element.

Optionally, the first message further includes a DNN of each session in the session currently performed by the terminal, so that, in the case that a supported session exists, the first AMF network element selects the SMF network element according to the DNN and information of a second network slice corresponding to the supported session.

505, the first AMF network element determines whether the first AMF network element supports a second network slice corresponding to one session or whether the first AMF network element supports a second network slice corresponding to all or part of the at least two sessions.

When the first AMF network element determines that the first AMF network element supports a second network slice corresponding to one session or supports second network slices corresponding to all sessions in at least two sessions, the first AMF network element does not perform step 506, and sends a first notification message to the second AMF network element, and performs step 507, the first AMF network element prepares a second network resource for the session corresponding to the supported second network slice.

In the case that the first AMF network element determines that the first AMF network element supports the second network slice corresponding to a partial session of the at least two sessions, the supported partial session is determined as a first partial session, and the other partial session not supported is determined as a second partial session. In this case, the first AMF network element performs step 506, and sends a first notification message to the second AMF network element that the second network slice corresponding to the second partial session is not supported. In addition, the first AMF network element performs step 507 to prepare the second network resource for the session corresponding to the supported second network slice.

And the first AMF network element performs step 506 to send a first notification message to the second AMF network element, where the first notification message does not support the second network slice corresponding to all the sessions, when the first AMF network element determines that the first AMF network element does not support the second network slice corresponding to one session or does not support the second network slice corresponding to all the sessions in the at least two sessions. And step 506 is not performed.

Step 505 specifically refers to a detailed description of step 406 in the embodiment shown in fig. 4, and will not be described herein again, for determining whether the first AMF network element supports the second network slice corresponding to one session or whether the first AMF network element supports the second network slice corresponding to all or part of at least two sessions.

506, the first AMF network element sends a first notification message to the second AMF network element if it is determined that the second network slice corresponding to the one session is not supported or the second network slice corresponding to all or part of the at least two sessions is not supported.

Step 506 may be described in detail with reference to step 407 in the embodiment shown in fig. 4, which is not described herein.

507, the first AMF network element prepares a second network resource for a session corresponding to the supported second network slice.

Specifically, in each case described in step 507 that satisfies execution of step 408, the first AMF network element prepares the second network resource for the session corresponding to the supported second network slice. The first AMF network element stores SMF network element identification, session identification and network slice related information; the first AMF network element selects a new SMF network element from the connected SMF network elements for the session of the terminal, and if the new SMF network element is different from the old SMF network element selected by the second AMF network element, the session context of the terminal supporting the session is to be synchronized between the new SMF network element and the old SMF network element, wherein the session context comprises session identification, DNN, qoS Flow information and the like; the new SMF network element selects a new UPF network element for the terminal, where the new UPF network element prepares transmission resources of the user plane, such as a transport layer address, a tunnel address, and the like, according to an indication of the new SMF network element.

For example, the first AMF network element may select the SMF network element according to the DNN carried by the first message and information of the second network slice corresponding to the supported session.

And 508, the second AMF network element performs handover.

Specifically, after the second receives the first notification message sent by the first AMF network element, the second AMF network element performs handover, specifically, the second AMF network element sends a handover request to a source RAN for establishing connection with the second AMF network element, and the source RAN sends a handover command to the terminal, where the handover command carries an identifier for identifying the target RAN. After receiving the handover command, the terminal starts to initiate a connection establishment request to the target RAN, and the source RAN (i.e., the RAN that sends the handover request is referred to in the embodiment of the present application) synchronizes with the transmitter state on the target RAN, such as a sequence number, a buffer queue, etc.; after the terminal is successfully connected to the target RAN, the terminal sends a switching confirmation message to the first AMF network element through the target RAN, the first AMF network element receives the switching confirmation message, and the first AMF network element updates the second network resource for the SMF network element selected by the terminal and the UPF network element corresponding to the SMF network element so as to ensure the bidirectional access of the uplink data tunnel and the downlink data tunnel.

509, the second AMF network element releases the first network resource corresponding to the one session or releases the first network resource corresponding to all or part of the sessions in the at least two sessions.

Specifically, after step 506, the second AMF network element determines that the first AMF network element does not support the second network slice corresponding to the one session or does not support the second network slice corresponding to all or part of the sessions in the at least two sessions, and then the second AMF network element releases the first network resources corresponding to the non-supported sessions, so as to reduce the waste of network resources.

The specific implementation manner of the second AMF network element releasing the first network resource in step 509 may refer to the detailed description of step 410 in the embodiment shown in fig. 4, which is not described herein.

510, in a case that the second AMF network element releases the first network resource corresponding to the one session or releases the first network resource corresponding to all or part of the at least two sessions, the second AMF network element sends a second notification message to the SMF network element associated with the session identifier of the one session or the SMF network element associated with the session identifier of all or part of the at least two sessions.

Step 510 may be described in detail with reference to step 411 in the embodiment shown in fig. 4, which is not described herein.

511, the SMF network element releases a third network resource occupied by a session of the terminal associated with the SMF network element.

Step 511 may be described in detail with reference to step 412 in the embodiment shown in fig. 4, and will not be described herein.

512, the SMF network element sends a third notification message to a UPF network element associated with a session identifier of the session, where the third notification message is used to notify the UPF network element that the terminal has moved out of a slice service range of the second AMF network element.

Specifically, in the case that the SMF network element releases a third network resource occupied by a session associated with the SMF network element, the SMF network element sends a third notification message to a UPF network element associated with a session identifier of the session. The UPF network element is informed to release the fourth network resource so as to reduce the waste of network resources at the UPF network element side.

Optionally, the SMF network element may determine, through a correspondence between a session identifier and a UPF network element identifier, a UPF network element that provides a service for the session; furthermore, the SMF network element may send a third notification message to the corresponding UPF network element and carry a session identifier of the session, so that the UPF network element releases the fourth network resource occupied by the session, so as to reduce the waste of network resources on the UPF network element side.

Correspondingly, the UPF network element receives a third notification message from the SMF network element.

513, the UPF network element releases fourth network resources occupied by the session associated with the UPF network element in the terminal.

The UPF network element determines, according to the session identifier carried in the third notification message, a fourth network resource occupied by the session indicated by the session identifier, for example, a transmission resource of a user plane related to the session, such as a transport layer address, a tunnel address, and the like. By releasing these fourth network resources by receiving the third notification message, waste of fourth network resources is reduced.

In the embodiment of the application, the first AMF network element sends the first notification message of the second network slice corresponding to the session of which the first AMF network element does not support the terminal to the second AMF network element, and after the second AMF network element receives the first notification message, the second AMF network element can be triggered in time to release the network resource occupied by the session, so that the waste of the network resource is reduced. In addition, the SMF network element is informed by the second AMF network element that the terminal moves out of the service range of the second AMF network element, the SMF network element is triggered to release the network resources occupied by the session in time, the waste of the network resources is reduced, the UPF network element is informed by the SMF network element that the terminal moves out of the service range of the second AMF network element, and the UPF network element is triggered to release the network resources occupied by the session in time, so that the waste of the network resources is further reduced.

The embodiment of the application also provides another session processing method, and a first AMF network element, a second AMF network element, an SMF network element, a UPF network element and a system based on the method. The method comprises the following steps: the method comprises the steps that a second AMF obtains information of a second network slice corresponding to a session currently performed by a terminal, wherein the session comprises one session or at least two sessions; the second AMF network element receives a first message from the network device, wherein the first message comprises an identifier of the first AMF network element to which the session is switched; and the second AMF network element releases the network resource corresponding to one session or releases the network resource corresponding to all or part of the at least two sessions under the condition that the second AMF network element does not support the second network slice corresponding to one session or the second network slice corresponding to all or part of the at least two sessions. Wherein, the network resource corresponding to the session or the network resource corresponding to all or part of the at least two sessions may be referred to as a first network resource.

Another session processing method described above is further described below with reference to fig. 6.

Referring to fig. 6, a schematic flow chart of a session processing method is provided for an embodiment of the present application based on the scene graph of fig. 2B. As shown in fig. 6, the method is implemented interactively by a first AMF network element, a second AMF network element, a terminal, a RAN, an NRF network element, an SMF network element, and a UPF network element. Wherein, in the scene that the terminal needs to switch AMF network element; the second AMF network element is an AMF network element for providing service for the terminal before switching, the first AMF network element is an AMF network element to which the terminal is to be switched, which is determined by the NRF network element, and the first AMF network element and the second AMF network element are different AMF network elements. For a session corresponding to a network slice not supported by the first AMF network element, the second AMF network element still reserves corresponding control plane resources for the SMF network element selected for the session, and the UPF network element selected for the session still reserves corresponding user plane resources.

601, the ran sends a handover request of the terminal to a second AMF network element.

The second AMF network element sends 602 a network element discovery request to the NRF network element.

603, the nrf network element sends the determined identifier of the first AMF network element providing the service for the terminal and the information of the first network slice supported by the first AMF network element to the second AMF network element.

Step 601, step 602, and step 603 may refer to specific descriptions of step 501, step 502, and step 503 in the embodiment shown in fig. 5, which are not described herein.

The second AMF network element determines whether the first AMF network element supports a second network slice corresponding to one session or whether the second AMF network element supports a second network slice corresponding to all or part of at least two sessions 604.

When the second AMF network element determines that the first AMF network element supports a second network slice corresponding to one session or supports a second network slice corresponding to all sessions in at least two sessions, the second AMF network element performs step 605 to send a first notification message to the first AMF network element, and does not perform step 608, the second AMF network element releases the first network resource occupied by the session corresponding to the second network slice not supported by the first AMF network element.

The second AMF network element determines that the supported partial session is a first partial session and the other partial session not supported is a second partial session when determining that the first AMF network element supports a second network slice corresponding to a partial session of the at least two sessions. In this case, the second AMF network element performs step 605, where the second AMF network element sends a first notification message to the first AMF network element, and performs step 608, where the second AMF network element releases the first network resource occupied by the session corresponding to the second network slice that is not supported by the first AMF network element.

In the case that the second AMF network element determines that the first AMF network element does not support the second network slice corresponding to one session or does not support the second network slice corresponding to all sessions in at least two sessions, the second AMF network element does not execute step 605, and the second AMF network element sends a first notification message of the supported second network slice corresponding to all or part of the sessions to the first AMF network element.

Step 604, how the second AMF network element specifically determines whether the first AMF network element supports the second network slice corresponding to one session or whether the first AMF network element supports the second network slice corresponding to all or part of the sessions in the embodiment shown in fig. 4, may be described in detail with reference to step 406, where the difference between the two embodiments is that the execution subject is different, step 604 is performed by the second AMF network element, and step 406 is performed by the first AMF network element, which is not described herein again.

605, the second AMF network element sends a first notification message to the first AMF network element when determining that the first AMF network element supports a second network slice corresponding to one session or supports a second network slice corresponding to all or part of at least two sessions.

Wherein, the first notification message is used for notifying the first AMF network element: the first AMF network element supports the second network slice corresponding to the one session or supports the second network slice corresponding to all or part of the at least two sessions, so that the first AMF network element can determine which second network slices the first AMF network element supports.

Optionally, the first notification message may further carry indication information, for example, supported slice, when the second AMF network element determines that the first AMF network element supports a second network slice corresponding to one session or supports a second network slice corresponding to all or part of at least two sessions. For example, the first notification message carries indication information and supported session identification; or carrying indication information and SMF network element identification associated with supported session identification; or, carrying indication information, supported session identification and SMF network element identification associated with the supported session identification.

Alternatively, the first notification message may be indicated by an information element (information element, IE), a flag, a cause value (cause), or the like, which is not limited by the embodiment of the present application. For example, the first notification message is a preset first cause value, and the first cause value is used to indicate that the first AMF network element supports a network slice corresponding to the session.

For example, it is premised that the session currently performed by the terminal includes a first session, a second session, and a third session. And for the first AMF network element, the first session and the second session can be provided with services, and the network slice corresponding to the third session is not supported, so that the first notification message sent by the second AMF network element to the first AMF network element comprises the identification of the first session, the identification of the second session and the corresponding first reason value.

Optionally, the first notification message carries DNN of a session corresponding to the second network slice supported by the first AMF network element, so that the first AMF network element selects the SMF network element according to the DNN and information of the second network slice corresponding to the supported session.

Correspondingly, the first AMF network element receives a first notification message sent by the second AMF network element.

The first AMF network element prepares 606 a second network resource for the session corresponding to the supported second network slice.

607, the second AMF network element performs handover.

Step 606 and step 607 may be specifically described with reference to step 507 and step 508 in the embodiment shown in fig. 5, and are not described herein.

608, the second AMF network element releases the first network resource corresponding to the one session or releases the first network resource corresponding to all or part of the at least two sessions.

Specifically, after step 604, the second AMF network element determines that the first AMF network element does not support the second network slice corresponding to one session or does not support the second network slice corresponding to all or part of the sessions in the at least two sessions, and then the second AMF network element releases the first network resources corresponding to the non-supported sessions, so as to reduce the waste of network resources.

In an alternative manner, in a case that the second AMF network element sends a first notification message to the first AMF network element, the second AMF network element immediately releases a first network resource corresponding to an unsupported session. Or in another alternative manner, in the case that the second AMF network element sends the first notification message to the first AMF network element, the second AMF network element releases the first network resource corresponding to the unsupported session after a preset period of time.

The detailed description of step 608 in which the second AMF network element releases the first network resource may refer to the detailed description of step 410 in the embodiment shown in fig. 4, which is not repeated herein.

609, in the case that the second AMF network element releases the first network resource corresponding to the one session or releases the first network resource corresponding to all or part of the at least two sessions, the second AMF network element sends a second notification message to the SMF network element associated with the session identifier of the one session or the SMF network element associated with the session identifier of all or part of the at least two sessions.

Step 609 may be described in detail with reference to step 411 in the embodiment shown in fig. 4, and will not be described herein.

And 610, the SMF network element releases a third network resource occupied by a session of the terminal associated with the SMF network element.

Step 610 may be described in detail with reference to step 412 in the embodiment shown in fig. 4, and will not be described herein.

611, the SMF network element sends a third notification message to a UPF network element associated with a session identifier of the session, where the third notification message is used to notify the UPF network element that the terminal has moved out of the slice service range of the second AMF network element.

612, the UPF network element releases fourth network resources occupied by the session associated with the UPF network element in the terminal.

Step 611 and step 612 may be described in detail with reference to step 512 and step 513 in the embodiment shown in fig. 5, which are not described herein.

In the embodiment of the application, the second AMF determines that the first AMF network element does not support the second network slice corresponding to all or part of the session in the terminal, so that the second AMF network element can release the network resources occupied by the unsupported session, and the waste of the network resources is reduced. In addition, the second AMF network element informs the SMF network element that the terminal moves out of the service range of the second AMF network element, and the SMF network element is triggered to release the network resources occupied by the session in time, so that the waste of the network resources is further reduced.

The embodiment of the application also provides a session processing method, a first AMF network element, a second AMF network element, an SMF network element, a UPF network element and a system based on the method. The method comprises the following steps: the method comprises the steps that a second AMF obtains information of a second network slice corresponding to a session currently performed by a terminal, wherein the session comprises one session or at least two sessions; the second AMF network element receives a first message from the network device, the first message including information of a first network slice supported by the first device; the second AMF network element releases network resources corresponding to the second session under the condition that the information of the first network slice does not contain the information of the second network slice corresponding to the second session; the second session is included in the sessions, and the sessions except the second session are the first session. Wherein the network resource corresponding to the session or the network resource corresponding to all or part of the at least two sessions may be referred to as a first network resource

The following describes a further session processing method described above with reference to fig. 7 and 8.

Referring to fig. 7, a schematic flow chart of a session processing method is provided for an embodiment of the present application based on the scene graph of fig. 2A. As shown in fig. 7, the method is implemented by interaction of a first AMF network element, a second AMF network element, a terminal, a RAN, and an SMF network element. Wherein, the terminal is in a connection state and serves as a second AMF network element; after the terminal is changed from the connection state to the idle state, the RAN determines a first AMF network element serving the terminal in the process of re-registering the network, and the first AMF network element and the second AMF network element are different AMF network elements. For a session corresponding to a network slice not supported by the first AMF network element, the second AMF network element and the SMF network element selected by the second AMF network element still reserve corresponding control plane resources for the session.

701, the terminal sends a registration request and information of a network slice corresponding to a session currently performed by the terminal to the RAN through radio resource control signaling.

The ran determines 702 a first AMF network element serving the terminal.

The ran sends 703 a registration request to the first AMF network element.

The specific description of step 701, step 702 and step 703 in the embodiment shown in fig. 4 may refer to the specific description of step 401, step 402 and step 403, which are not described herein.

The first AMF network element sends 704 a first message to the second AMF network element, the first message comprising information of a first network slice supported by the first AMF network element.

Specifically, after receiving a registration request sent by the RAN, the first AMF network element sends a first message to the second AMF network element, where the first message includes information of a first network slice supported by the first AMF network element. So that the second AMF network element determines whether the information of the first network slice contains information of a second network slice corresponding to the session in the terminal.

Optionally, the first message is a context acquisition request, configured to acquire a context of the terminal.

705, the second AMF network element determines whether the information of the first network slice comprises information of a second network slice.

Wherein the session currently ongoing by the terminal comprises one session or at least two sessions. For the case that the current session of the terminal comprises one session, the first AMF network element judges whether the information of the first network slice comprises the information of the second network slice corresponding to the session; for the case that the current session of the terminal includes at least two sessions, the first AMF network element determines whether the information of the first network slice includes information of a second network slice corresponding to all or part of the at least two sessions.

For the case of a session, if the second AMF network element determines that the information of the first network slice includes information of the second network slice corresponding to the session, step 706 is executed, where the second AMF network element sends a first notification message to the first AMF network element.

For the case of at least two sessions, if the second AMF network element determines that the information of the first network slice includes information of a second network slice corresponding to all or part of the at least two sessions, step 706 is executed, where the second AMF network element sends a first notification message to the first AMF network element.

In other words, the second AMF network element determines whether the information of the first network slice includes the information of the second network slice corresponding to the session according to the information of the first network slice supported by the first AMF network element, so as to determine whether the first AMF network element does not support the second network slice due to the deployment reason of the network slice of the first AMF network element.

Optionally, when the second AMF network element determines that the first AMF network element supports the second network slice corresponding to the one session or supports the second network slice corresponding to all or part of the at least two sessions, step 706 is executed to send the first notification message to the first AMF network element.

706, the second AMF network element sends a first notification message to the first AMF network element.

Wherein, the first notification message is used for notifying the first AMF network element: the information of the first network slice comprises information of a second network slice corresponding to a first session, wherein the first session is one session of a terminal or all or part of the at least two sessions, and the second session is one session or one session except the first session.

Optionally, the first notification message includes indication information, e.g., supported slice, and a session identification of the first session.

Optionally, the first notification message further includes a DNN of the first session, so that the first AMF network element selects the SMF network element according to the DNN and information of the second network slice corresponding to the supported session.

707, the first AMF network element determines whether the information of the third network slice comprises information of the second network slice.

Wherein the information of the third network slice is information of allowed network slices allocated to the terminal, for example, allowed NSSAI. For example, the first AMF network element obtains information of a third network slice from a network slice selection function (network slice selection function, NSSF) network element.

For any one of the first sessions included in the first notification message, that is, the information of the second network slice corresponding to the session is included in the information of the first network slice, if the information of the allowed third network slice does not include the information of the second network slice corresponding to the session, it indicates that the first AMF network element does not support the second network slice corresponding to the session. If the information of the allowed third network slice includes the information of the second network slice corresponding to the session, the information indicates that the first AMF network element supports the network slice corresponding to the session.

Through this determination, the first AMF network element may determine a session in which the first AMF network element may provide a service and a session in which the first AMF network element may not provide a service. In this embodiment, the first AMF network element does not support the network slice corresponding to the third session, and the first AMF network element supports the network slice corresponding to the session other than the third session in the first session.

708, the first AMF network element sends a fourth notification message to the second AMF network element.

The fourth notification message is configured to notify that the first AMF network element does not support the second network slice corresponding to the third session. Wherein the third session is all or part of the first session. So that the second AMF network element determines a third session not supported by the first AMF network element and releases the first network resource occupied by the third session.

Optionally, the first AMF network element performs step 709 in case the third session comprises fewer sessions than the first session.

709, the first AMF network element sends a registration accept message to the terminal.

And 710, the terminal sends a registration completion message to the first AMF network element.

Step 709 and step 710 may be specifically described with reference to step 408 and step 409 in the embodiment shown in fig. 4, which are not described herein.

The second AMF network element releases 711 the first network resource.

After step 705, if the session currently performed by the terminal is a session, and the information of the first network slice does not include the information of the second network slice corresponding to the session, the embodiment does not execute steps 706 to 710, and executes step 711, where the second AMF network element releases the first network resource occupied by the session.

If the current session of the terminal is at least two sessions, the information of the first network slice includes the information of the second network slice corresponding to the first session, where the first session is included in the at least two sessions. Then, if the first session is the same as at least two sessions, the embodiment performs step 706 after step 705 and temporarily does not perform step 711. If the first session is less than the at least two sessions, the embodiment performs step 706 and step 711 after step 705, and the second AMF network element releases the first network resources occupied by the sessions other than the first session in the at least two sessions, so as to reduce the waste of network resources.

Under the condition that the second AMF network element receives the fourth known message sent by the first AMF network element, the second AMF network element executes step 711 to release the first network resource occupied by the third session, so as to reduce the waste of network resources.

The specific implementation manner of the second AMF network element releasing the first network resource in step 711 may refer to the detailed description of step 410 in the embodiment shown in fig. 4, which is not described herein.

712, in case the second AMF network element releases the first network resources occupied by the second session and the third session, the second AMF network element sends a second notification message to the SMF network element associated with the session identity of each of the second session and the third session.

713, the SMF network element releasing third network resources occupied by sessions of the terminal associated with the SMF network element.

Step 712 and step 713 may be described in detail with reference to step 411 and step 412 in the embodiment shown in fig. 4, and are not described herein.

In the embodiment of the application, by determining that the first AMF network element does not support the second network slice corresponding to all or part of the session in the terminal, the second AMF network element can release the network resources occupied by the unsupported session, so that the waste of the network resources is reduced. In addition, the second AMF network element informs the SMF network element that the terminal moves out of the service range of the second AMF network element, and the SMF network element is triggered to release the network resources occupied by the session in time, so that the waste of the network resources is further reduced.

Referring to fig. 8, a flow chart of a session processing method is provided for an embodiment of the present application based on the scene graph of fig. 2B. As shown in fig. 8, the method is implemented by interaction of a first AMF network element, a second AMF network element, a terminal, a RAN, an NRF network element, an SMF network element, and a UPF network element. Wherein, in the scene that the terminal needs to switch AMF network element; the second AMF network element is an AMF network element for providing service for the terminal before switching, the first AMF network element is an AMF network element to which the terminal is to be switched, which is determined by the NRF network element, and the first AMF network element and the second AMF network element are different AMF network elements. For the session corresponding to the network slice not supported by the first AMF network element, the second AMF network element and the second AMF network element still reserve corresponding control plane resources for the SMF network element selected by the session, and the UPF network element selected by the session still reserves corresponding user plane resources.

801, the ran sends a handover request of the terminal to a second AMF network element.

802, the second AMF network element sends a network element discovery request to the NRF network element.

803, the nrf network element sends the determined identification of the first AMF network element providing the service for the terminal and the information of the first network slice supported by the first AMF network element to the second AMF network element.

Step 801, step 802, and step 803 may be specifically described with reference to step 501, step 502, and step 503 in the embodiment shown in fig. 5, which are not described herein.

The second AMF network element determines whether the information of the first network slice comprises information of a second network slice 804.

805, the second AMF network element sends a first notification message to the first AMF network element.

806, the first AMF network element determines whether the information of the third network slice comprises information of the second network slice.

807, the first AMF network element sends a fourth notification message to the second AMF network element.

808, the second AMF network element releases the first network resource.

Step 804, step 805, step 806, step 807, and step 808 may refer to specific descriptions of step 705, step 706, step 707, step 708, and step 711 in the embodiment shown in fig. 7, and are not described herein.

809, the first AMF network element prepares a second network resource for the session corresponding to the supported second network slice.

Step 806 determines that the first AMF network element does not support the network slice corresponding to the third session, and if the first AMF network element supports the network slice corresponding to the session other than the third session in the first session, the session corresponding to the second network slice supported in step 809 is the session other than the third session in the first session.

The specific implementation of preparing the second network resource in step 806 may refer to the specific description of step 507 in the embodiment shown in fig. 5, which is not described herein.

810, the second AMF network element performs handover.

Step 810 may be specifically described with reference to step 508 in the embodiment shown in fig. 5, and will not be described herein.

811, in the case that the second AMF network element releases the first network resource, the second AMF network element sends a second notification message to the SMF network element associated with the session identifier of each of the second session and the third session.

812, the SMF network element releases a third network resource occupied by a session of the terminal associated with the SMF network element.

Step 811 and step 812 may be described in detail with reference to step 411 and step 412 in the embodiment shown in fig. 4, which will not be described herein.

813, the SMF network element sends a third notification message to a UPF network element associated with a session identifier of the session, where the third notification message is used to notify the UPF network element that the terminal has moved out of the slice service range of the second AMF network element.

814, the UPF network element releases fourth network resources occupied by the session associated with the UPF network element in the terminal.

Step 813 and step 814 may be described in detail with reference to step 512 and step 513 in the embodiment shown in fig. 5, and are not described herein.

In the embodiment of the application, by determining the second network slice corresponding to the session of the terminal which is not supported by the first AMF network element, the second AMF network element can release the network resources occupied by the session which is not supported, so that the waste of the network resources is reduced. In addition, the second AMF network element informs the SMF network element that the terminal moves out of the service range of the second AMF network element, and the SMF network element is triggered to release the network resources occupied by the session in time, so that the waste of the network resources is further reduced.

The solutions provided in the embodiments of the present application are mainly described above from the point of interaction between different network elements. It will be appreciated that the first AMF network element, the second AMF network element, the SMF network element or the UPF network element, in order to implement the above functions, comprise corresponding hardware structures and/or software modules for performing the respective functions. The various example units and algorithm steps described in connection with the embodiments disclosed herein may be embodied as hardware or a combination of hardware and computer software. Whether a function is implemented as hardware or computer software driven hardware depends upon the particular application and design constraints imposed on the solution. Those skilled in the art may implement the described functionality using different approaches for each particular application, but such implementation is not to be considered as beyond the scope of the embodiments of the present application.

The embodiment of the present application may divide the functional modules or functional units of the first AMF network element, the second AMF network element, the SMF network element, or the UPF network element according to the above method examples, for example, each functional module or functional unit may be divided corresponding to each function, or two or more functions may be integrated into one processing module or processing unit. The integrated modules or units described above may be implemented in hardware or in software functional modules. It should be noted that, in the embodiment of the present application, the division of the modules or units is schematic, which is merely a logic function division, and other division manners may be implemented in actual practice.

Fig. 9 is a schematic block diagram of one possible first AMF network element 900 according to an embodiment of the present application, in case of using different functional modules or units. The first AMF network element 900 may be the first AMF network element 900 involved in the methods described above, capable of performing the steps performed by the first AMF network element in the methods of fig. 3-8, e.g., the first AMF network element 900 may be capable of performing the processes 301 and 302 of fig. 3, the processes 403, 404, 405, 406, 407, 408 of fig. 4, the processes 504, 505, 506, 507, 508 of fig. 5, the processes 605, 606, 607 of fig. 6, the processes 703, 704, 706, 707, 708, 709, 710 of fig. 7, the processes 805, 806, 807, 809, 810 of fig. 8, and/or other processes for the techniques described herein.

As shown in fig. 9, the first AMF network element 900 includes:

the processing unit 901 receives, through the receiving unit 902, a first message from a second AMF network element, where the first message includes information of a second network slice corresponding to a session currently performed by the terminal, and the session includes one session or at least two sessions;

the processing unit 901 sends, through the sending unit 903, a first notification message to the second AMF network element, where the second network slice corresponding to the one session is determined not to be supported or the second network slice corresponding to all or part of the at least two sessions is not supported, where the first notification message is used to notify the second AMF network element: the first AMF network element does not support the second network slice corresponding to the one session or does not support the second network slice corresponding to all or part of the at least two sessions.

In case of integrated modules or units, fig. 10 is a schematic block diagram of one possibility of the first AMF network element 1000 of an embodiment of the present application. The first AMF network element 1000 comprises: a processing unit 1002, and a communication unit 1003. The processing unit 1002 is configured to control and manage the actions of the first AMF network element 1000, e.g., the processing unit 1002 is configured to support the first AMF network element 1000 to perform the processes 301 and 302 in fig. 3, the processes 403, 404, 405, 406, 407, 408 in fig. 4, the processes 504, 505, 506, 507, 508 in fig. 5, the processes 605, 606, 607 in fig. 6, the processes 703, 704, 706, 707, 708, 709, 710 in fig. 7, the processes 805, 806, 807, 809, 810 in fig. 8, and/or other processes for the techniques described herein. The communication unit 1003 is configured to support communication between the first AMF network element 1000 and a second AMF network element or other network elements. The first AMF network element 1000 may further comprise a storage unit 1001 for storing program code and data of the first AMF network element 1000.

The processing unit 1002 may be a processor or controller, such as a central processing unit (central processing unit, CPU), general purpose processor, digital signal processor (digital signal processor, DSP), application Specific Integrated Circuit (ASIC), field programmable gate array (field programmable gate array, FPGA) or other programmable logic device, transistor logic device, hardware components, or any combination thereof. Which may implement or perform the various exemplary logic blocks, modules, and circuits described in connection with this disclosure. The processor may also be a combination that performs the function of a computation, e.g., a combination comprising one or more microprocessors, a combination of a DSP and a microprocessor, and the like. The communication unit 1003 may be a communication interface, a transceiver, a transceiving circuit, or the like, where the communication interface is generally called, and in a specific implementation, the communication interface may include a plurality of interfaces, for example, may include: an interface between the first AMF network element 1000 and a traffic management unit and/or other interfaces. The storage unit 1001 may be a memory.

When the processing unit 1002 is a processor, the communication unit 1003 is a communication interface, and the storage unit 1001 is a memory, the network component management unit according to the embodiment of the present application may be the first AMF network element 1100 shown in fig. 11.

Referring to fig. 11, the first AMF network unit 1100 includes: a processor 1102, a communication interface 1103, a memory 1101. Optionally, the first AMF network element 1100 may further comprise a bus 1104. Wherein the communication interface 1103, the processor 1102 and the memory 1101 may be interconnected by a bus 1104; the bus 1104 may be a peripheral component interconnect standard (peripheral component interconnect, PCI) bus, or an extended industry standard architecture (extended industry standard architecture, EISA) bus, among others. The bus 1104 may be divided into an address bus, a data bus, a control bus, and the like. For ease of illustration, only one thick line is shown in FIG. 11, but not only one bus or one type of bus.

Concepts related to the technical solutions provided in the embodiments of the present application related to the first AMF network element 900 in fig. 9, the first AMF network element 1000 in fig. 10, and the first AMF network element 1100 in fig. 11, for explanation and detailed description and other steps, refer to descriptions about these contents in the foregoing methods or other embodiments, which are not repeated herein.

Fig. 12 is a schematic block diagram of one possible second AMF network element 1200 according to an embodiment of the present application, in case of using different functional modules or units. The second AMF network element 1200 may be the second AMF network element 1200 involved in the methods described above, capable of performing the steps performed by the second AMF network element in the methods of fig. 3-8, e.g., the second AMF network element 1200 may be capable of performing the processes 301, 302, 303 in fig. 3, the processes 404, 405, 407, 410, 411 in fig. 4, the processes 501, 502, 503, 504, 506, 509, 510 in fig. 5, the processes 601, 602, 603, 604, 605, 607, 608, 609 in fig. 6, the processes 704, 705, 706, 708, 711, 712 in fig. 7, the processes 801, 802, 803, 804, 805, 807, 808, 810, 811 in fig. 8, and/or other processes for the techniques described herein.

As shown in fig. 12, the second AMF network element 1200 includes:

the processing unit 1201 sends a first message to a first AMF network element through the sending unit 1202, where the first message includes information of a second network slice corresponding to a session currently performed by the terminal, and the session includes one session or at least two sessions;

the processing unit 1201 receives, through the receiving unit 1203, a first notification message from the first AMF network element, where the first notification message is used to notify the second AMF network element: the first AMF network element does not support the second network slice corresponding to the session or does not support the second network slice corresponding to all or part of the sessions in the at least two sessions;

the processing unit 1201 is further configured to release network resources corresponding to the one session or release network resources corresponding to all or part of the at least two sessions.

In case of integrated modules or units, fig. 13 is a possible schematic block diagram of a second AMF network element 1300 according to an embodiment of the present application. The second AMF network element 1300 comprises: a processing unit 1302, and a communication unit 1303. The processing unit 1302 is configured to control and manage the actions of the second AMF network element 1300, e.g., the processing unit 1302 is configured to support the second AMF network element 1300 to perform the processes 301, 302, 303 in fig. 3, the processes 404, 405, 407, 410, 411 in fig. 4, the processes 501, 502, 503, 504, 506, 509, 510 in fig. 5, the processes 601, 602, 603, 604, 605, 607, 608, 609 in fig. 6, the processes 704, 705, 706, 708, 711, 712 in fig. 7, the processes 801, 802, 803, 804, 805, 807, 808, 810, 811 in fig. 8, and/or other processes for the techniques described herein. The communication unit 1303 is configured to support communication between the second AMF network element 1300 and the first AMF network element, the SMF network element, or other network elements. The second AMF network element 1300 may further comprise a storage unit 1301 for storing program codes and data of the second AMF network element 1300.

The processing unit 1302 may be a processor or controller, such as a CPU, general purpose processor, DSP, ASIC, FPGA or other programmable logic device, transistor logic device, hardware components, or any combination thereof. Which may implement or perform the various exemplary logic blocks, modules, and circuits described in connection with this disclosure. The processor may also be a combination that performs the function of a computation, e.g., a combination comprising one or more microprocessors, a combination of a DSP and a microprocessor, and the like. The communication unit 1303 may be a communication interface, a transceiver, or a transceiver circuit, where the communication interface is generally called, and in a specific implementation, the communication interface may include a plurality of interfaces, for example may include: an interface between the second AMF network element 1300 and a traffic management unit and/or other interfaces. The storage unit 1301 may be a memory.

When the processing unit 1302 is a processor, the communication unit 1303 is a communication interface, and the storage unit 1301 is a memory, the network element management unit according to the embodiments of the present application may be the second AMF network element 1400 shown in fig. 14.

Referring to fig. 14, the second AMF network element 1400 includes: a processor 1402, a communication interface 1403, a memory 1401. Optionally, the second AMF network element 1400 may also include a bus 1404. Wherein the communication interface 1403, the processor 1402 and the memory 1401 may be connected to each other through a bus 1404; bus 1404 may be a PCI bus or an EISA bus, among others. The bus 1404 may be divided into an address bus, a data bus, a control bus, and the like. For ease of illustration, only one thick line is shown in fig. 14, but not only one bus or one type of bus.

Concepts related to the technical solutions provided in the embodiments of the present application related to the second AMF network element 1200 in fig. 12, the second AMF network element 1300 in fig. 13, and the second AMF network element 1400 in fig. 14, for explanation and detailed description, and other steps, refer to descriptions about these contents in the foregoing methods or other embodiments, which are not repeated herein.

The embodiment of the present application further provides an SMF network element, where the structure schematic diagram of the SMF network element is similar to the structure schematic diagram of the first AMF network element or the second AMF network element, as shown in fig. 15, fig. 16, and fig. 17. The modules or devices included in the SMF network element may correspond to the actions performed by the SMF network element involved in the foregoing method, which are not described herein.

The embodiment of the present application further provides a UPF network element, where the structural schematic diagram of the UPF network element is similar to the structural schematic diagrams of the first AMF network element or the second AMF network element, as shown in fig. 18, fig. 19, and fig. 20. The module or the device included in the UPF network element may correspondingly execute the actions performed by the UPF network element related to the above method, which are not described herein.

The steps of a method or algorithm described in connection with the disclosure of the embodiments disclosed herein may be embodied in hardware, or may be embodied in software instructions executed by a processor. The software instructions may be comprised of corresponding software modules that may be stored in random access memory (random access memory, RAM), flash memory, read Only Memory (ROM), erasable programmable read only memory (erasable programmable ROM), electrically Erasable Programmable Read Only Memory (EEPROM), registers, hard disk, a removable disk, a compact disc read only memory (CD-ROM), or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. In addition, the ASIC may be located in a first AMF network element, a second AMF network element, an SMF network element, or a UPF network element. Of course, the processor and the storage medium may reside as discrete components in a first AMF network element, a second AMF network element, an SMF network element, or a UPF network element.

Those of skill in the art will appreciate that in one or more of the above examples, the functions described in the embodiments of the present application may be implemented, in whole or in part, in software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, produces a flow or function in accordance with embodiments of the present application, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by a wired (e.g., coaxial cable, fiber optic, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a digital video disc (digital video disc, DVD)), or a semiconductor medium (e.g., a Solid State Disk (SSD)), or the like.

The foregoing embodiments have been provided for the purpose of illustrating the embodiments of the present application in further detail, and it should be understood that the foregoing embodiments are merely illustrative of the embodiments of the present application and are not intended to limit the scope of the embodiments of the present application, and any modifications, equivalents, improvements, etc. made on the basis of the technical solutions of the embodiments of the present application are included in the scope of the embodiments of the present application.

Claims

1. A session processing method, comprising:

the first access and mobility management function network element receives a first message from the second access and mobility management function network element, wherein the first message comprises information of a network slice corresponding to a session of the terminal;

and the first access and mobility management function network element sends a first notification message to the second access and mobility management function network element under the condition that the network slice corresponding to the session is not supported, wherein the first notification message is used for triggering and releasing the network resource corresponding to the session.

2. The method according to claim 1, wherein before the first access and mobility management function network element sends the first notification message to the second access and mobility management function network element, the method further comprises:

The first access and mobility management function network element determines that the network slice corresponding to the session is not supported under the condition that the information of the network slice supported by the first access and mobility management function network element does not contain the information of the network slice corresponding to the session;

or, the first access and mobility management function network element determines that the network slice corresponding to the session is not supported when the information of the allowed network slice allocated to the terminal does not contain the information of the network slice corresponding to the session.

3. The method according to claim 1 or 2, characterized in that the first message further comprises a mobility management context, a permanent identification of the terminal, a session identification of the session and/or an identification of a session management function network element associated with the session.

4. A method according to any of claims 1-3, characterized in that the first message further comprises a data network name DNN of the session.

5. The method according to any of claims 1-4, wherein the network resources comprise network resources occupied by the session on the second access and mobility management function and network resources occupied by the session on the session management function associated with the session.

6. The method according to any of claims 1-5, wherein the information of the network slice corresponding to the session selects auxiliary information for a single network slice corresponding to the session.

7. The method according to any of claims 1-6, wherein the first notification message comprises an identification of the session and a cause value, wherein the cause value is used to indicate that the first access and mobility management function network element does not support a network slice corresponding to the session.

8. A session processing method, comprising:

the second access and mobility management function network element sends a first message to the first access and mobility management function network element, wherein the first message comprises the information of a network slice corresponding to a session of the terminal;

the second access and mobility management function network element receives a first notification message from the first access and mobility management function network element, wherein the first notification message is used for triggering and releasing network resources corresponding to the session;

and the second access and mobility management function network element releases the first network resource corresponding to the session.

9. The method of claim 8, wherein the method further comprises:

The second access and mobility management function network element sends a second notification message to the session management function network element associated with the session, where the second notification message is used to trigger the session management function network element to release a second network resource corresponding to the session.

10. The method according to claim 8 or 9, wherein the second access and mobility management function network element releases the first network resource corresponding to the session, comprising:

the second access and mobility management function network element immediately releases the first network resource under the condition of receiving the first notification message; or,

and the second access and mobility management function network element releases the first network resource after a preset time period under the condition of receiving the first notification message.

11. The method according to any of claims 8-10, wherein the first message further comprises a mobility management context, a permanent identity of the terminal, a session identity of the session and/or an identity of a session management function network element associated with the session.

12. The method according to any of claims 8-11, wherein the first message further comprises a data network name, DNN, of the session.

13. The method according to any of claims 8-12, wherein the information of the network slice corresponding to the session selects auxiliary information for a single network slice corresponding to the session.

14. The method according to any of claims 8-13, wherein the first notification message comprises an identification of the session and a cause value, wherein the cause value is used to indicate that the first access and mobility management function network element does not support a network slice corresponding to the session.

15. An access and mobility management function network element, characterized by comprising means for performing the method of any of the preceding claims 1-14.

16. A computer readable storage medium comprising instructions which, when executed by a processor, implement the method of any of claims 1-14.